Hydrocarbon producing formations typically have sand commingled with the hydrocarbons to be produced. For various reasons, it is not desirable to produce the commingled sand to the earth's surface. Thus, sand control completion techniques are used to prevent the production of sand.
Gravel packing is one method for controlling sand production. Although there are variations, gravel packing usually involves placing a sand screen around the section of the production string containing the production inlets. This section of the production string is aligned with perforations. Gravel slurry, which is typically gravel particulates carried in a viscous transport fluid, is pumped through the tubing into the formation and the annulus between the sand screen and the casing or between the sand screen and the open hole. The deposited gravel holds the sand in place preventing the sand from flowing to the production tubing while allowing the production fluids to be produced therethrough.
In multi-zone wells or in a well having multiple flow sections, flow control devices have been used to control fluid flow through orifices formed between the tubing bore and an annulus between the tubing and casing. However, if sand face completion equipment including gravel packing is installed, then the annulus is typically filled, which makes it difficult to position such flow control devices in the proximity of sand control equipment. Accordingly, the formation fluid must first flow generally radially through the sand control device before flowing to the flow control device. One option is to install the flow control device inside a tubing bore in the proximity of the production zone. However, this reduces the available flow area for production flow.
Three-way sub systems with sliding sleeves inside an internal isolation string have also been used for zonal isolation. A screen wrapped sliding sleeve is also a common system. For example, U.S. Pat. No. 3,741,300 discloses a sliding sleeve within a screen assembly. However, the '300 patent describes a 3-way sub system and it is specifically intended for stand alone screen applications (no pumping).
U.S. Pat. No. 5,337,808 discloses an apparatus where the screen wrapping is placed directly over and around the flow control device. U.S. Pat. No. 6,220,357 discloses a similar apparatus.
U.S. Pat. No. 5,609,204 and U.S. Pat. No. 5,579,844 disclose an apparatus having sliding sleeves inside sand control screens in combination with components for supporting gravel packing operations such as polished bore receptacles and port closure sleeves.
U.S. Pat. No. 5,865,251 discloses an isolation valve “adjacent” or “interior” of the screen assembly which covers the apertures of the valve.
U.S. Pat. No. 6,405,800 discloses an isolation valve that is positioned in the screen base pipe underneath the screen jacket.
U.S. Pat. No. 6,343,651 and U.S. Pat. No. 6,446,729 disclose a flow control valve that is coupled to a screen assembly. It is not surrounded by and is offset from the screen wrapping. The valve is in fact not integral to the screen assembly but an added component which is hydraulically coupled to the screen and base pipe annulus to control flow into the main bore.
U.S. Pat. No. 6,464,006 discloses an apparatus having flow screens with flow closure members. The figures presented in U.S. Pat. No. 6,464,006 illustrate a three-way sub system, but both ends of the isolation pipe are shown affixed to the screen assembly.
U.S. Pat. No. 6,719,051 and U.S. Pat. No. 7,096,945 disclose a screen assembly with openings in the base pipe and a valve associated with the openings in the base pipe to control flow through the openings.
U.S. Publication No. 2007/0084605 discloses a screen assembly with at least one production screen valve.
There is still a need for improved flow control devices that provide incremental choking of the flow and that may be used in sand control completion equipment. There is also a need for a coupling tool that supports a flowpath between two screens without the use of an isolation string.